Method and means for supplying chlorine gas



July 10, 1934- F. c. sczHwnaLKESy METHOD AND MEANS FOR SUPPLYINGCHLORINE GAS Filed Feb. 23, 1952 ,D lNvi-:NToR 3701/3 GLLMMUA 2,ATTORNEY Patented July l0, 1934 IWIETHD AND MEANS FR SUPPLYHNG CHLURHNIEGAS l'tranz C. Schmelkes, Bloomeld, N. J., assigner to Wallace d;Tier-nan Company, nc., Belleville, N. ll., a corporation of New YorkApplication February 23, 1932, Serial No. 594,586 8 Claims. (Cl.2lll-23) This invention relates to supplying a regulated :Elow ofchlorine gas, and has for its object the provision of a method and meansfor controlling the now of chlorine gas; more particularly the inventionaims Ato provide a method and means whereby foreign impurities inchlorine gas are removed and consequently do not deposit in and clog upvalves or other parts employed in controlling or metering the iloW ofchlorine in chlorinating apparatus, such as is used for treating Water.

Chlorine is a highly reactive material and tends to react with thematerial, such as steel, composing the cylinder in which it is confinedand with. impurities, such as oils, which are present in commercialchlorine. As a result the gas drawn o from cylinders of liquid chlorinecontains small amounts of ferric chloride, chlorinated oils, such ashexachlorethane, and other products. These chlorine-containing materialsform sticky.. gunimy deposits which are apt to clog or choke the lineorifices used for controlling and/or metering the ow of chlorine.

One of the most frequent causes of the clogging up of pressure reducingvalves and other nowcontrolling oriiices is the liquefaction of chlorinein the supply line extending from the cylinder of liquid chlorine tosuch valve. The pressure behind the valve or other orifice may besubstantially the liquefaction pressure at ordinary room temperatures,so that a drop in the temperature in the supply line may causecondensation of chlorine in the line. This liquid chlorine dissolves anymetallic chlorides, chlorinated oils, etc., which are present, andcarries them along to the valve oriiice. At that point the reduction inpressure causes the liquid chlorine to evaporate, and such evaporationcauses a deposit of thematerial previously dissolved in the liquidchlorine.

I have found that it is possible to remove such gummy material fromchlorine gas by passing the gas over an adsorptive material, such assilica gel, activated carbon or the like. The separation of such gummymaterial by adsorptive substances depends on the property ofselectivity, characteristic of adsorption phenomena, If chlorine gas ispassed through or over silica gel, it will adsorb chlorine untilequilibrium is reached, the amount of chlorine adsorbed being dependentupon the temperature and pressure. If other substances are passedthrough the silica gel, which are more readily adsorbed thereby, thereis a replacement of a part of the adsorbed chlorine by such substances.

rThe readiness with which a gas is adsorbed is largely an inversefunction of its volatility, and that, in turn, is largely dependent onthe molecular weight of the substance. Thus, a substance likehexachlorethane is less volatile and more readily adsorbed thanchlorine. Hexachlorethane, CCl3.CCl3, boils or sublimes underatmospheric pressure at around 185 C. and has a molecular weight of 237.Chlorine boils at 33.6 C. and has a molecular weight of 71.

The customary method of controlling flow of chlorine fom a cylinder ofliquid chlorine involves the use of one or more flow-controllingrestrictions beyond the Valve on the end of the cylinder, the rst beingusually a pressure-reducing valve. The cylinder valve is customarilyopened wide, so that, even if deposition of gummy material occurs in thelatter valve it will not appreciably interfere with the now of chlorinetherethrough. Then, by placing a iilter of adsorptive material in thechlorine line between the cylinder valve and the rst flow-controllingrestriction, the gummy materials are removed before the chlorine reachestherectriction where deposition of suchmaterials might otherwise ocourand result in clogging or seriously interfering with the flow ofchlorine therethrough.

It is desirable to place the lter in as close proximity to the reducingvalve as possible to eliminate as far as practicable any condensation ofliquid chlorine between the lilter and the reducing valve and\thepossibility ofv the formation of metallic chlorides, chlorinated oilsand the like, between the lter and the reducing valve. Advantageously,the line between the filter and the reducing valve is formed of or linedwith vitreous material, such as glass, to avoid the formation ofmetallic chlorides.

Many chlorinators, such, for example, as those now in use for treatingwater, are equipped with now meters of the type in which the rate of ow95 is determined by the drop in pressure across a restricted orice.Partial choking of such orifice not only reduces the ow of chlorine butthe meter reads too high, and regulation of the chlorine supply by suchmeter readings mayl easily result in adding to the water insufficientchlorine to produce sterilization. The choking of the meter orice is aptto have more serious consequences than the choking of otherrestrictions, as in the latter case the meter indicates 105 immediatelywhen proper ow of chlorine ceases, whereas when the'meter itself is outof adjust-v ment there is nothing to give notice of that fact. Hence,while for reasons above stated it is usually desirable to place the lterbetween the cylinder 110 valve and the pressure reducing valve, thefilter may on the other hand be inserted between the pressure reducingvalve and the meter and still retain much of the advantages resultingfrom the elimination of gummy materials from the chlorine.

Provided the chlorine is dry and the purication takes place at a pointwhere access of moisture isimpossible, activated carbon is preferable tosilica gel, as carbon has a larger capacity for the gummy impurities.If, however, the chlorine contains moisture, either originally or byreason of the fact that the lter is located so that access of moistureis not entirely prevented, silica gel is preferable as the adsorbingmaterial. Any other adsorbent or adsorbents may be used provided theirchemical and physical properties permit.

While the chief impurities to be eliminated are ferric chloride andchlorinated oils, there may be and doubtless are others. Someimpurities, such as nitrogen and oxygen,'are not extracted by silica orthe like. However, such impurities are not deposit-forming, and, hence,do not tend to clog the valve orices or other orifices and other workingparts. While some of the impurities, such as ferric chloride, are not tobe classed as gums, the term gummy materials is employed in thespecification and claims to include anything capable of forming anadherent deposit to reduce or clog a flow-controlling orice or the likeand also the constituents of such deposits which are non-adherent perse.

A full understanding of the invention can best be given by a descriptionthereof in connection with a somewhat diagrammatic sectional showing ofparts of an illustrative embodiment of the invention in the accompanyingdrawing.

'Ihe invention is shown as applied to a chlorinating apparatus of thegeneral type illustrated and described in U. S. Patent No. 1,777,986 ofWallace.

A cylinder of liquid chlorine is indicated at 1, and chlorine gas is ledtherefrom through a shut 01T valvey 2 and tube 3 to the purifying devicedesignated generally as 4. From such device the gas passes upwardly by atube 5 through the bottom of a Water tray 6. This water tray is adaptedto support a bell jar and other parts as disclosed in the abovementioned Wallace patent. Of these parts only the float-controlledpressure reducing valve, by which a desired reduced gas pressure ismaintained within the bell jar, is shown, comprising a float 7 whichoperates a needle valve 8 controlling the flow of gas from the end ofthe tube 5, as illustration of the other parts is not necessary to afull understanding of the principles and mode of operation of thepresent invention.

The purifying device comprises a cylinder 9 of metal or other suitablematerial closed at its ends by screw caps 10 and 11. The cylinder isnlled, except for packing layers of glass wool 12 and 13 at top andbottom, with suitable adsorptive material 14, such as silica gel.

Since, for reasons given above, it is desirabley to avoid entirely, orat least to restrict to a minimum, contact between the chlorine gas andmetals between the point at which the chlorine leaves the adsorptivepurifying material and the orifice where deposition of adherent materialwould be deleterious, the tube 5 may have an inner surface of glass. Asshown, the tube 5 is formed of an outer tube 15 of silver and an innertube 16 of glass. The silver tube is enlarged at .the same reason it isadvantageous that the adsorptive material should, as far as practicable,be granular in form and as free from dust and ne particles as possible.

In operation, the valve 2 is opened wide or fairly wide so that cloggingthereof is practically impossible and the desired pressure control isobtained by the pressure reducing needle valve 8.

What is claimed is:

1. The method of supplying a regulated flow of chlorine gas, whichcomprises passing such gas through a filter of adsorptive materialadapted to remove gummy materials therefrom, and passing the so puriedgas through a flow-controlling orifice so small in size as to becomeclogged by gummy substances deposited from impure chlorine gas passedtherethrough.

2. The method of supplying a regulated ow of chlorine gas, whichcomprises passing chlorine gas at substantially the vapor pressure ofliquid chlorine at the prevailing room temperature through a filter ofadsorptive material adapted to remove gummy materials from such chlorinegas, and passing the so purified gas through a flow-controlling orificeso small in size as to become clogged by gummy substances deposited fromimpure chlorine gas passed therethrough.

3. The method of controlling the flow of chlorine gas from liquidchlorine, which comprises permitting chlorine gas to vaporize from theliquid chlorine, passing the said gas through a filter of adsorptivematerial, thereby removing gummy materials therefrom, and passing -theso purified gas through a now-controlling orifice so small in size as tobecome clogged by gummy substances deposited from impure chlorine gaspassed therethrough.

4. The method of supplying a regulated flow of chlorine from a containerof liquid chlorine, which comprises passing chlorine gas from suchcontainer over material which has the capability of physically adsorbingonto its active surface impurities capable of gumming up small orificesand delicate valves, and substantially immediately thereafter passingthe so-purined gas through a pressure reducing orifice so small in sizeas to become clogged by gummy substances deposited from impure chlorinegas passed therethrough.

5. 'I'he method of supplying a regulated flow of chlorine gas from acontainer of liquid chlorine, which comprises passing chlorine gas fromsaid container through a relatively wide open valve, then passing thegas through a filter of adsorptive material adapted to remove gummymaterials from the chlorine, and then passing the filtered gas through anow-controlling orice so small in size as to become clogged by gummysubstances deposited from impure chlorine gas passed therethrough, thevalve having a ow passage large enough to avoid clogging by thedeposition of gummy material, and the lter acting to remove suchmaterial which might otherwise clog such flow-controlling orifice.

6. An apparatus for supplying a regulated flow of chlorine gas, whichcomprises a container of liquid chlorine, and a iow line leading fromthe container which includes a lter of adsorptive material adapted toremove gummy materials 150 reeaaes from chlorine gas discharged from thecontainer, the pressure in said lter being substantially the vaporpressure of liquid chlorine at the prevailing room temperature, andmeans for controlling the now o chlorine gas from said filter comeprising a pressure reducing valve having in normal operation a passagetherethrough so small in size as to become clogged by gummy substancesdeposited from impure chlorine gas passed therethrough.

'7. An apparatus for supplying a regulated flow of chlorine gas, whichcomprises a container oi liquid chlorine, and a ow line leading from thecontainer which includes a lter of adsorptive material adapted to removegummy materials from chlorine gas discharged from the container, meansfor controlling the ow of chlorine gas from said iilter comprising apressure reducing valve having in normal operation a passagetherethrough so small in size as to become clogged by gummy substancesdeposited from impure chlorine gas passed therethrough, and a conduitbetween said lter and said means having walls substantially whollyvitreous in character.

8. An apparatus for supplying a regulated flow

